The invention relates to mass storage interfaces for electronic devices such as computers. More particularly, it relates to expanding the personal computer AT Attachment/IDE interface to support multiple mass storage devices on a single channel.
One unrelenting trend in personal computing is the continuing evolution of peripheral devices, in particular, mass storage devices. Mass storage devices such as hard disks, CD-ROMS, DVD-ROMS, ZIP drives, and LS-120 drives, to name a few, are constantly improving. Not only is the amount of storage per unit cost increasing, but also so is the speed at which the personal computer (PC) accesses the media. Consequently, more and more consumers are adding mass storage devices to their personal computers. Unfortunately, some fundamental limitations are preventing these consumers from optimizing their systems.
While high speed mass storage interfaces such as SCSI (Small Computer Systems Interface) exist, the cost of outfitting a computer to have a SCSI interface has keep consumers from widely adopting this standard. While these alternative interfaces for expanding the number of mass storage devices are available for personal computers, they are of limited or no use in notebook computers due to cost, size, power consumption, and cable requirements. Most personal computers are configured with an AT Attachment (ATA) mass storage interface (also known as Integrated Device Electronics (IDE) interface) that is maintained by a standards organization, the American National Standards Institute (ANSI). This ATA standard has allowed the PC to be widely adopted but the standard only provides limited mass storage support especially in the number of drives supported. Because other mass storage standards exist for expanding the number of drives for PC""s (such as SCSI), any improvements in the ATA standard interface have dealt mainly with increasing the access speeds of the interface and not with increasing the number of mass storage devices.
Consumers are demanding, however, both the ability to have more ATA mass storage devices in their notebooks and thinner, lighter notebooks. This diametric set of desires is forcing designers and manufacturers to rethink the architecture and layout of notebook computers. In order to satisfy the consumer, a full product line of notebooks and accessories should be available. Notwithstanding, the full product line should share the same peripherals due to competitive cost and time-to-market constraints. Further, several companies have organizations that need several different models of notebooks and there is a strong need to have module interchangeability in order to facilitate keeping stock of spare parts to a minimum.
New notebooks having large displays can incorporate two drive bays in addition to a boot hard disk due to a larger footprint. The thinner notebooks, to keep weight to a minimum, can only support the boot hard disk and possibly one internal drive bay. However, the architecture should provide for external drive bays that can be connected to the thinner notebook. All of the notebook models should support common docking stations and port replicators. Some mass storage devices are accessed only occasionally so the consumers are also requesting that multiple drive bays be available in the docking station to store and preferably access them. The mass storage devices that are used in the docking station need preferably to be usable and interchangeable with mass storage devices in the notebook computer or external drive bay.
Additionally, when replacing modules, the consumer is demanding near foolproof operation. In the past, consumers had to turn off computers before removing accessories. With the advent of xe2x80x98hot-swapxe2x80x99 PC card peripherals that are interchangeable at will, consumers are now expecting that other peripherals such as mass storage devices be hot-swappable. This hot-swap feature is especially valuable when a notebook computer battery is low and a consumer needs to insert an additional battery in the mass storage drive bay to keep the computer running a program. Another time when hot-swapping is valuable is when a program requires a CD-ROM for program data and the user wants to save output from the program on a removable media such as a ZIP or LS-120 drive.
As more and more mass storage devices become available, the desire of the consumer to want to access multiple devices without interchanging them will intensify. New applications such as photo editing will require multiple drives to access both image and program files at the same time. Thus a need exists to be able to support more than 2 ATA mass storage devices either in a single computer or with the use of docking stations or external drive bays, preferably with hot-swap support.
An electronic device has a host processor system having an AT Attachment (ATA) mass storage interface having a single channel. The electronic device further has at least three mass storage device ports that are capable of accepting ATA mass storage devices. A method for interfacing the mass storage devices to the ATA single channel interface provides the host processor access to all ATA mass storage devices.